The selection of a route plays an important role in the minimization of the energy consumption of a motor vehicle. While there may be various criteria by which a route can be determined, navigation systems are most commonly configured in such a way that the shortest and/or the fastest route from a starting point to a destination is determined.
In some cases, it may be that the shortest route is the most efficient with respect to energy consumption. However, if the shortest route leads through an urban area, for example, where increased energy consumption arises due to frequent traffic-related stopping and starting, the route may be less energy efficient. Further, the attributes of the route, such as the permissible speed, interruptions in the traffic flow due to traffic regulations (such as traffic light, stop signs, pedestrians, etc.), the differences in altitude, and the properties of the vehicle and/or the driving behavior of the driver may also have an effect on the efficiency of the vehicle's energy consumption.
Various examples exist of methodologies for determining an energy efficient route. For example, U.S. Pat. No. 5,913,917 discloses a method for estimating the energy consumption of a motor vehicle during a journey from a starting point to a destination along a predefined route in order to estimate the range of an electrically or conventionally operated motor vehicle. In this context, the predefined route is split into segments within which the conditions such as maximum speed, gradient, etc. are constant, and the segments comprise a maximum one intersection or junction. On the basis of data about the gradient, vehicle speed, anticipated traffic density, weather conditions, etc., a fuel consumption value is determined for each segment, with a predefined driving style of the driver also being taken into account. The sum of the consumption values which are determined for the individual segments constitutes the entire predicted fuel consumption on the predefined route.
As additional examples, DE 102007059120 A1 and DE 102007059121 A1 disclose methods for determining an energy-consumption-optimized route from a starting point to a destination, wherein energy consumption values are assigned to at least some of the elements of map data which model a traffic route network and which have an acceleration-dependent and/or speed-dependent component. In order to detect driver-specific influences, one of a plurality of predefined possible driving styles (sporty, conservative or defensive or energy-saving) is assumed.